The underlying myth of B12 absorption

When many people take supplements or ingest certain foods in their diet, they just assume that their body is getting the full dosage of the nutrients each contains.

However, this isn’t exactly the case as many factors can affect nutrient absorption rate.

Nutrient absorption factors

According to the National Center on Health, Physical Activity and Disability (NCHPAD), the rate at which your body is able to take in certain vitamins and minerals can change based on other nutrients consumed at the same time. For instance, to increase the absorption rate of vitamin D, you should take it with calcium, say the experts at Harvard Medical School. And if you want to counteract taking in too much sodium, then adding potassium at the same time should do the trick.

Harvard health professionals add that folate enhances the absorption of vitamin B12, a nutrient found naturally “in meat, eggs, milk, and other foods of animal origin.” While getting all of the necessary vitamins and minerals is important to overall health, this particular vitamin carries some major importance all on its own.

Importance of vitamin B12

The National Institutes of Health Office of Dietary Supplements (ODS) shares that vitamin B12 is critical to a healthy diet, largely because it “helps keep the body’s nerve and blood cells healthy and helps make DNA, the genetic material in all cells.” In other words, if you don’t get enough vitamin B12 in your diet, your cells aren’t as strong and fit as they could be.

The ODS goes on to say that getting adequate levels of vitamin B12 in your diet also helps prevent the development of a condition called megaloblastic anemia. This form of anemia is characterized by “red blood cells that are larger than normal” mixed with a low red blood cell count, according to Healthline. The result is feelings of fatigue.

Factors inhibiting B12 absorption

We already know from Harvard that B12 absorption can be increased by taking folate (another B vitamin, this one found in higher amounts in chickpeas, liver, pinto beans, lentils, spinach, asparagus, and avocado, among others). However, there are some factors that can actually inhibit the rate in which your body takes in this key nutrient. One involves medications.

The ODS reports that the taking of certain medications can lower the amount of B12 your body is able to absorb. These include:

Because intrinsic factor (a protein the stomach makes) aids the body in the absorption of B12 as well, individuals with pernicious anemia—a condition which the National Heart, Lung, and Blood Institute states involves the lack of intrinsic factor—have a harder time getting the necessary amount of this vitamin.

Without the B12, it’s harder for the cells to divide the way they should so they’re unable to leave the bone marrow and carry fresh oxygen to the rest of the body. In the short term, this creates fatigue. Long term, the result is potential damage to vital organs like the brain and heart.

Vitamin B12 recommendations

To enjoy maximum health, the ODS recommends that teens and adults get 2.4 micrograms (mcg) of B12 daily. This amount increases slightly for pregnant women (2.6 mcg) and women who are breastfeeding (2.8 mcg).

Foods high in B12 include clams, liver, trout, salmon, tuna, milk, yogurt, cheese, eggs, ham, and chicken. You can also find it in some fortified foods such as breakfast cereals and nutritional yeasts. Supplements are another option for increasing vitamin B12 intake as well.

Again, to enhance absorption (which is only “56 percent of a 1 mcg oral dose” according to the ODS), it is recommended that this nutrient be taken in conjunction with folic acid. However, folic acid intake should be limited to 1,000 mcg, says the ODS, to avoid making brain-related symptoms of a B12 deficiency worse.